Went to an estate sale this morning, boys and girls, and while I'm not sure these have any value, they sure are cool! I have three or four of each envelope shown here, and the backs of the envelopes say "Porto-server Chicago, Ill. 1942". The color on these is incredible and they're in great shape. The back also has three lines for the return address.
I can imagine how seeing one of these being handed to you would have brightened your day if you were a soldier and away from your loved ones.